Well, we've finally gotten to the point at the new house where I need some help. I'll give some details first.
The new house is built on a slab. Sometime after the original owners constructed the house, they must have realized that we are, after all, on the fringes of Tornado Alley and that the house, being built on a slab, didn't have a basement. They subsequently built a detached garage a short distance from the house that has a storm shelter under it.
The storm shelter is a room approximately 10x12, built of cement block with poured (and, I assume, reinforced) concrete floor and roof slabs. The floor has a built-in sump pump basin, which ties into my problem. The walls and floor of the shelter have been painted with a white, thick, presumably waterproofing paint that is chalking and scaling very badly.
Now, the problem is that the shelter has about 2' of water in it at all times. It appears that, sometime after construction of the shelter, the water table must have risen to it's present level, about 2' into the shelter. I pumped the shelter out soon after buying the house but, since water kept leaking in, I unpluged the sump pump to see how far it would rise. When I initially pumped it out, it had about 3' of water in it, which is now down to the above mentioned 2', presumably because of the very dry summer so far.
Now, for the big question. Since the house doesn't have a basement and we do live in a tornado-prone area, the wife is after me to get the shelter into useable condition. If I can get the shelter pumped out and find out exactly where the water is coming in and patch any cracks, then I just have to deal with the water seeping through the block and floor. Provided I can get most of the existing paint off the block, do you think something like UGL's Drylox would suffice for waterproofing the shelter? Given that there only appears to be about 2' of water, the pressure from the ground water shouldn't be too bad but, since it is groundwater, it will be constant and steady. I know Drylox works well for seepage but how about the steady, constant pressure from the groundwater?
Another question is, since the shelter does have a sump basin, would I be better off drilling a few holes in the walls/bottom of the basin to give the groundwater a safe place to go? My problem with this is that if something happens to the sump pump or we lose power, the shelter would then fill up very quickly since the water now has an unobstructed flow into the shelter. I plan on a battery back-up for the pump but, as we all know, Murphy strikes at the worst times and, with my luck, we'll be in the shelter, the power will go off and the battery backup will decide to crap out.
Digging the sides of the shelter out to fill with gravel for drainage, which I don't know if it was done or not when constructed, is out. This is because, after initial construction, the garage was added onto on one side and the back, with the additions concrete-slabbed and sticking out over the side and back of the shelter. Because of this, excavation would be extensive and expensive, requiring considerable manpower and bracing of the slabs. Most of our savings went into downpayments and improvements and is practically non-existant at this time.
So, what say you ARFCOM? Am I out of luck with this or does someone have any bright ideas? I'd really like to get this shelter useable since, with the concrete roof being well tied down and about 1.5' thick, we should be able to withstand storms that would devastate everything around us. If it's not going to work, however, I'm not wasting much time on it. As always, thanks for looking and for any and all assistance.
Bub